Wireless communication systems, such as the 3rd Generation (3G) of mobile telephone standards and technology, are well known. An example of such 3G standards and technology is the Universal Mobile Telecommunications System (UMTS), developed by the 3rd Generation Partnership Project (3GPP) (www.3gpp.org). The 3rd generation of wireless communications has generally been developed to support macro-cell mobile phone communications. Such macro cells utilise high power base stations (Node Bs in 3GPP parlance) to communicate with remote (often mobile/portable) wireless Communication units within a relatively large coverage area. Typically, wireless communication units, or User Equipment (UE) as they are often referred to in 3G parlance, communicate with a Core Network (CN) of the 3G wireless communication system via a Radio Network Subsystem (RNS). A wireless communication system typically comprises a plurality of radio network subsystems, each radio network subsystem comprising one or more cells to which UEs may attach, and thereby connect to the network. Each macro-cellular RNS further comprises a controller, in the form of a Radio Network Controller (RNC), operably coupled to the one or more Node Bs, via an lub interface.
The RNC is operably coupled to a Serving GPRS (General Packet Radio Service) Support Node (SGSN) within the core network via an lu interface. The SGSN is operably coupled to a Gateway GPRS Support Node (GGSN), also located within the core network, via a Gn interface. The GGSN provides an interface Gi between the backbone GPRS network and external packet data networks, such as the Internet.
In order for a UE to access, say, the Internet via the 3G wireless communication system, the UE must activate a PDP (Packet Data Protocol) context. A PDP context is a data structure present on both the current SGSN for that UE, and a GGSN that provides access to the required external packet data network, which for this example comprises the Internet.
To activate a PDP context, the UE selects an Access Point Name (APN) corresponding to the required external packet data network, (e.g. the Internet). The selection of the APN may be based on configuration information or by user input. The UE then sends a GPRS session management message in the form of an Activate PDP Context Request message comprising the APN to the SGSN. Further details for GPRS management messages may be found in 3GPP Technical Specification 24.008.
Upon receipt of the Activate PDP Context Request message, the SGSN performs a DNS (Domain Name Server) lookup for the APN, in order to locate the address of the appropriate GGSN. The SGSN then initiates PDP context activation within itself and the appropriate GGSN, and sends details of the activated PDP context to the UE. The UE is then able to access, for example, the Internet using the activated PDP context within the GGSN.
Lower power (and therefore smaller coverage area) femto cells (or pico-cells) are a recent development within the field of wireless cellular communication systems. Femto cells or pico-cells (with the term femto cells being used hereafter to also encompass pico-cells or similar) are effectively communication coverage areas supported by low power base stations (otherwise referred to as Access Points (APs)). These femto cells are intended to be able to be piggy-backed onto the more widely used macro-cellular network and support communications to UEs in a restricted, for example ‘in-building’, environment.
In this regard, a femto cell that is intended to support communications according to the 3GPP standard will hereinafter be referred to as a 3G femto cell. Similarly, an access controller intended to support communications with a low power base station in a femto cell according to the 3GPP standard will hereinafter be referred to as a 3rd generation access controller (3G AC). Similarly, an Access Point intended to support communications in a femto cell according to the 3GPP standard will hereinafter be referred to as a 3rd Generation Access Point (3G AP).
Typical applications for such 3G APs include, by way of example, residential and commercial (e.g. office) locations, communication ‘hotspots’, etc., whereby an AP can be connected to a core network via, for example, the Internet using a broadband connection or the like. In this manner, femto cells can be provided in a simple, scalable deployment in specific in-building locations where, for example, network congestion at the macro-cell level may be problematic.
In a femto cell scenario, an RNS typically comprises multiple 3G Access Points (3G AP), performing a number of functions generally associated with a base station or Node B and a controller in a form of a 3G Access controller (3G AC). The 3G AP is typically coupled to the 3G Access Controller via the Internet. The 3G Access Controller is then typically coupled to the core network (CN) via an lu interface. In this manner, the 3G AP is able to provide voice and data services to a cellular handset, such as a UE, in a femto cell in contrast to the macro cell, in the same way as a conventional Node-B, but with the deployment simplicity of, for example, a Wireless Local Area Network (WLAN) access point.
Conventionally, in order for a UE within a femto cell to access, say, the Internet via the 3G wireless communication system, the UE must activate a PDP context within the SGSN and GGSN, and access the Internet (or other external packet data network) via the appropriate GGSN of the core network. Accordingly, data being uploaded from the UE to the Internet is sent via the 3G AP over the Internet to the 3G Access Controller, before being routed via the SGSN and GGSN back to the Internet. Similarly, data being downloaded from the Internet is routed via the GGSN and SGSN to the 3G Access Controller, where it is transmitted over the Internet to the 3G AP.
As will be appreciated by a skilled artisan, this current approach for accessing the Internet and other external packet data networks via femto cells is inefficient, since typically 3G APs already have substantially direct access to the Internet. Therefore, the current technique is wasteful of network resources that could otherwise be utilised more effectively.
It is also known for local packet data networks to exist within residential and commercial environments. For example, a local network within a residential environment may comprise a home network linking, for example, a personal computer, a printer, etc. Similarly, in a commercial environment, a local network may comprise a local area network such as a corporate intranet or the like. It is contemplated that a femto AP may be operably coupled to such a local network, and enable access to such a local network. However, current approaches for accessing packet data networks via cellular communication networks such as a 3G network do not enable a UE to access such a local network via a femto AP, even if the UE is located within the femto cell supported by that femto AP.